


Somatosensory Perception

by CaffieneKitty



Category: Sherlock (TV)
Genre: For Science!, Gen, Gen or Pre-Slash, M/M, Romantic Friendship, Sensuality, Trust, Writing on Skin, blindfold
Language: English
Status: Completed
Published: 2010-09-01
Updated: 2010-09-01
Packaged: 2017-12-29 19:44:08
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,048
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1009304
Author URL: https://archiveofourown.org/users/CaffieneKitty/pseuds/CaffieneKitty
Summary: <blockquote class="userstuff">
              <p>It's an exercise in observation, one he can't do by himself.</p>
            </blockquote>





	Somatosensory Perception

**Author's Note:**

> _Originally posted on Livejournal September 1, 2010_

>   
>  _somatosensory /so·ma·to·sen·sory/ - pertaining to sensations received in the skin and deep tissues._   
>  -Dorland's Medical Dictionary 2007   
> 

 

"Comb. Yours. The small black one you carry in your coat pocket."

Another rueful chuckle confirms Sherlock is right, and the line of tiny John-smelling pressure points disappear from his chest.

It's an exercise in observation, one he can't do by himself. Sherlock's eyes are covered by the most effective blindfold they can fashion, and John has been touching him with things to identify without Sherlock seeing them or handling them himself, and without any hint from John. He's pleased with the results.

A cool flat object rests against the bridge of his nose. He doesn't need to tilt his head to tell what it is. "My mobile. Again."

The flat object disappears and something brushes Sherlock's bottom lip. He captures it in his mouth, smirking. _Thumb, John's thumb, left, blunt nail, clean, hint of orange, real orange, not disinfectant soap, marmalade from toast._ He keeps the thumb pinned between his teeth at the first joint, pressing his tongue to the pad trying to see if he can discern the lines of John's thumbprint. Loop, or high-arched whorl, or-

The thumb pulls out from between his teeth. He leans forward to recapture it, but something pointed is poked under his chin. Unexpected; his teeth snap together.

"John?"

John is silent. No hints. As requested.

The point is small, hard, pressing in under his jaw line, not sharp enough to be a knife. Too sharp to be a stir rod from his chemistry equipment. Knitting needle or letter opener, possible, but... the faintest rattle in John's shifting grip, plastic on plastic.

 _A ball-point pen, perhaps?_ Sherlock dips his head down in an attempt to catch the object in his mouth and confirm his deduction, but the point just digs deeper.

"D'you trust me?" John asks, breaking the rules.

Sherlock doesn't answer, but raises his chin slightly.

John chuckles.

The point moves -- definitely a ball-point pen, he wonders what colour the ink is -- tracing along the underside of his jaw to the left side of his neck, the briefest of pauses, then slowly trails down his jugular. He could easily pull away from the pressure and the mark John is making, raise his hand up and take the pen away but he doesn't.

John draws the pen across his throat now, just under the laryngeal prominence. The pressure makes his throat work in reflex like he's choking, and he murmurs something about tracheotomies. John laughs. The pen slides over and down the other side of his throat.

In the darkness under the blindfold, Sherlock can sense the track the pen is leaving. He maps it in his mind's eye; a framework of lines in three dimensions, flexing as he breathes. He wishes again he knew the colour of the ink. For now, the lines glow, following the brighter point of pressure from the pen tip.

The lines down his throat trace the blood vessel, cross his windpipe, continue down the other side, angular. The pen follows his clavicle to his shoulder -- John hesitates there, the pen will leave a darker spot, a jag in the line -- before sliding down the inside of Sherlock's right arm, down his right wrist to where his hand rests beside him, unrestrained and unmoving.

"Your hands are free, you know," John reminds him, softly, unnecessarily, pen tracing between the tendons of Sherlock's wrist. "You can stop me anytime you want."

"I know."

Some small noise, lips sliding over teeth, breath on Sherlock's fingers. John is smiling. The pen traces back up his arm, winding through its earlier path in an imitation of the medical caduceus.

"You're going to have to keep your scarf and coat on around people for a while or they might see this." John says, low-toned beside his head, a hint of impishness in his voice as he traces over the top of Sherlock's right shoulder. "Ink doesn't wash off easily."

"What if I want them to see?"

The pen stops, mid-stroke. John's out-blown breath tickles Sherlock's earlobe, slides up past his nose; residual morning mint, tea, marmalade again, like John's thumb. "I'd meant this as something just for us. Private." John says. Pleased, yet somehow wistful. Odd.

Sherlock tips his chin up and back. "If you insist."

The pen swirls in a tight spiral at the tip of Sherlock's right clavicle before moving on, down to the base of his throat and down his sternum.

As the pen slides across each rib, side to side, lines trace themselves in Sherlock's mind like the pendulum of a metronome. He thinks of fingerprints, of symbols of kinship and alliance, ink on skin to bind and strengthen, runes, traditions, spells. Mystical nonsense, but at the moment he doesn't mind.

Sherlock's skin shivers as the pen slips down just past the edge of his lowest rib to track along his abdomen. Not a tickle, too strong a stroke to tickle, nearly strong enough to hurt, but not quite. Surgical strength and precision. The pen slides back up between his ribs and draws small idle loops on his sternum.

"An artist traditionally signs his work, John," Sherlock prompts.

There is the briefest of pauses before the pen tip swoops up to his left pectoral muscle and the pen zigzags in the doctor's scribble of a signature directly over Sherlock's heart. Sentimental. Sherlock finds he doesn't mind that either.

There is a gust across Sherlock's throat as John sighs and lifts the pen. "Want to see?" he says.

Sherlock nods, and John pushes the blindfold off.

Sherlock looks down at his chest. The lines of pen strokes he has mapped in his head aren't there, just a hint of pinked skin from the last pen-traced whorl, and John's signature slowly fading as he watches. Sherlock puts a hand to his own throat, finger tracing the first stroke along his jaw line.

"You could tell the ink was out, that the pen wasn't writing anything, couldn't you? That's why you weren't stopping me." John sounds wistful again. "You knew I wasn't leaving a mark on you at all."

Sherlock puts his fingers to the last faint trace of John's signature, catching it under his hand.

"Yes," he lies.


End file.
